Evidence for evolution 10.4 Flashcards
what is evolution
Evolution Is the theory that describes the way in which organisms evolve, or change, over many many years as a result of natural selection.
Why would species change over time
A species changes over time to have a more advantages phenotype for the environment in which it lives.
organisms best suited to their environment are more likely to survive and reproduce, passing on their characteristics to their offspring
what influenced Charles Darwin to first think about evolution as a slow process
Darwin read the ‘principles of geology’ a book written by his friend Charles Lyell, a Scottish geologist, in this book he suggested fossils where evidence of animals that lived millions of years ago.
In it Lyell also popularised the principle of uniformitarianism. This is the idea that the land was shaped by forces that can still be seen today such as wind erosion and sedimentation over a long period of time. This prompted Darwin to think about evolution as a slow process, one in which small changes gradually accumulate over very long periods of time
who else was developing a theory of evolution at the same time as Darwin
alfred wallace
what evidence is there for evolution
- palaeontology-the study of fossils and the fossil records
- comparative anatomy-the study of similarities and differences between organisms anatomy
- comparative biochemistry-similarities and differences between the chemical makeup of organisms
what evidence is there provided by the fossil records to support the theory of evolution
- older fossils are more simple where as newer fossils are more complex
^supports theory that complex life evolved from simple life - plant fossils appear earlier than animals fossils, due to animals needing plants to live
- by studying anatomy of fossils, can show how related organisms evolved from common ancestor
^same can be said for living animals and extinct animals
what is comparative anatomy
comparative anatomy is the study of similarities and differences in the anatomy of different living species
- what is a homologous structure in reference to anatomy
- what is an example of this
- a structure that appears superficially different in different organisms
- but has same underlying structure.
- example is the pentadactyl limb of vertebrates
what is an explanation of homologous structure
the animals that have the homologous structures have a common ancestor and so those homologous structures have evolved from the same structure in the common ancestor
what does the presence of homologous structures provide evidence for
Divergent evolution
What is divergent evolution and when does this occur
This describes how, from a common ancestor, different species have evolved, each with a different set of adaptive features. This type of evolution will occur when closely related species diversify to adapt to new habitats as a result of migration or lass of habitat
what is Comparative biochemistry
- the study of similarities and differences in proteins and other molecules that control life processes.
what is embrology and how can it provide evidence for evolutionary relationships
the study of embryos
An embryo is an unborn (unhatched) animal in its earliest phases of development. Embryos of many different animals look very similar and it is often difficult to tell them apart. This shows that the animals develop in a similar way, implying that the processes of embryonic development have a common origin and the animals share a common ancestry but have gradually evolved different traits
How can comparative biology be used to provide evidence for evolutionary relationships
although molecules can change over time, some important molecules are highly conserved (remain almost unchanged) among species. Slight changes that occur in these molecules can help to identify evolutionary links
Two of the most common molecules studied are cytochrome c, a protein involved in respiration and ribosomal RNA
What is the hypothesis of neutral evolution
It states that most of the variability in the structure of a molecule does not affect its function. This is because of the variability occurs outside of the molecules functional region
There accumilation is not affected by natural selection
As a result neutral substitutions occur at a fairly regular rate, although that rate is different for different molecules
